diff --git a/spec/features/oauth_spec.rb b/spec/features/oauth_spec.rb
new file mode 100644
index 000000000..967956cc8
--- /dev/null
+++ b/spec/features/oauth_spec.rb
@@ -0,0 +1,190 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe 'Using OAuth from an external app' do
+  let(:client_app) { Doorkeeper::Application.create!(name: 'test', redirect_uri: 'http://localhost/', scopes: 'read') }
+
+  context 'when the user is already logged in' do
+    let!(:user) { Fabricate(:user) }
+
+    before do
+      sign_in user, scope: :user
+    end
+
+    it 'when accepting the authorization request' do
+      params = { client_id: client_app.uid, response_type: 'code', redirect_uri: client_app.redirect_uri, scope: 'read' }
+      visit "/oauth/authorize?#{params.to_query}"
+
+      # It presents the user with an authorization page
+      expect(page).to have_content(I18n.t('doorkeeper.authorizations.buttons.authorize'))
+
+      # Upon authorizing, it redirects to the apps' callback URL
+      click_on I18n.t('doorkeeper.authorizations.buttons.authorize')
+      expect(page).to have_current_path(/\A#{client_app.redirect_uri}/, url: true)
+
+      # It grants the app access to the account
+      expect(Doorkeeper::AccessGrant.exists?(application: client_app, resource_owner_id: user.id)).to be true
+    end
+
+    it 'when rejecting the authorization request' do
+      params = { client_id: client_app.uid, response_type: 'code', redirect_uri: client_app.redirect_uri, scope: 'read' }
+      visit "/oauth/authorize?#{params.to_query}"
+
+      # It presents the user with an authorization page
+      expect(page).to have_content(I18n.t('doorkeeper.authorizations.buttons.deny'))
+
+      # Upon denying, it redirects to the apps' callback URL
+      click_on I18n.t('doorkeeper.authorizations.buttons.deny')
+      expect(page).to have_current_path(/\A#{client_app.redirect_uri}/, url: true)
+
+      # It does not grant the app access to the account
+      expect(Doorkeeper::AccessGrant.exists?(application: client_app, resource_owner_id: user.id)).to be false
+    end
+  end
+
+  context 'when the user is not already logged in' do
+    let(:email)    { 'test@example.com' }
+    let(:password) { 'testpassword' }
+    let(:user)     { Fabricate(:user, email: email, password: password) }
+
+    before do
+      user.confirm!
+      user.approve!
+    end
+
+    it 'when accepting the authorization request' do
+      params = { client_id: client_app.uid, response_type: 'code', redirect_uri: client_app.redirect_uri, scope: 'read' }
+      visit "/oauth/authorize?#{params.to_query}"
+
+      # It presents the user with a log-in page
+      expect(page).to have_content(I18n.t('auth.login'))
+
+      # Failing to log-in presents the form again
+      fill_in 'user_email', with: email
+      fill_in 'user_password', with: 'wrong password'
+      click_on I18n.t('auth.login')
+      expect(page).to have_content(I18n.t('auth.login'))
+
+      # Logging in redirects to an authorization page
+      fill_in 'user_email', with: email
+      fill_in 'user_password', with: password
+      click_on I18n.t('auth.login')
+      expect(page).to have_content(I18n.t('doorkeeper.authorizations.buttons.authorize'))
+
+      # Upon authorizing, it redirects to the apps' callback URL
+      click_on I18n.t('doorkeeper.authorizations.buttons.authorize')
+      expect(page).to have_current_path(/\A#{client_app.redirect_uri}/, url: true)
+
+      # It grants the app access to the account
+      expect(Doorkeeper::AccessGrant.exists?(application: client_app, resource_owner_id: user.id)).to be true
+    end
+
+    it 'when rejecting the authorization request' do
+      params = { client_id: client_app.uid, response_type: 'code', redirect_uri: client_app.redirect_uri, scope: 'read' }
+      visit "/oauth/authorize?#{params.to_query}"
+
+      # It presents the user with a log-in page
+      expect(page).to have_content(I18n.t('auth.login'))
+
+      # Failing to log-in presents the form again
+      fill_in 'user_email', with: email
+      fill_in 'user_password', with: 'wrong password'
+      click_on I18n.t('auth.login')
+      expect(page).to have_content(I18n.t('auth.login'))
+
+      # Logging in redirects to an authorization page
+      fill_in 'user_email', with: email
+      fill_in 'user_password', with: password
+      click_on I18n.t('auth.login')
+      expect(page).to have_content(I18n.t('doorkeeper.authorizations.buttons.authorize'))
+
+      # Upon denying, it redirects to the apps' callback URL
+      click_on I18n.t('doorkeeper.authorizations.buttons.deny')
+      expect(page).to have_current_path(/\A#{client_app.redirect_uri}/, url: true)
+
+      # It does not grant the app access to the account
+      expect(Doorkeeper::AccessGrant.exists?(application: client_app, resource_owner_id: user.id)).to be false
+    end
+
+    context 'when the user has set up TOTP' do
+      let(:user) { Fabricate(:user, email: email, password: password, otp_required_for_login: true, otp_secret: User.generate_otp_secret(32)) }
+
+      it 'when accepting the authorization request' do
+        params = { client_id: client_app.uid, response_type: 'code', redirect_uri: client_app.redirect_uri, scope: 'read' }
+        visit "/oauth/authorize?#{params.to_query}"
+
+        # It presents the user with a log-in page
+        expect(page).to have_content(I18n.t('auth.login'))
+
+        # Failing to log-in presents the form again
+        fill_in 'user_email', with: email
+        fill_in 'user_password', with: 'wrong password'
+        click_on I18n.t('auth.login')
+        expect(page).to have_content(I18n.t('auth.login'))
+
+        # Logging in redirects to a two-factor authentication page
+        fill_in 'user_email', with: email
+        fill_in 'user_password', with: password
+        click_on I18n.t('auth.login')
+        expect(page).to have_content(I18n.t('simple_form.hints.sessions.otp'))
+
+        # Filling in an incorrect two-factor authentication code presents the form again
+        fill_in 'user_otp_attempt', with: 'wrong'
+        click_on I18n.t('auth.login')
+        expect(page).to have_content(I18n.t('simple_form.hints.sessions.otp'))
+
+        # Filling in the correct TOTP code redirects to an app authorization page
+        fill_in 'user_otp_attempt', with: user.current_otp
+        click_on I18n.t('auth.login')
+        expect(page).to have_content(I18n.t('doorkeeper.authorizations.buttons.authorize'))
+
+        # Upon authorizing, it redirects to the apps' callback URL
+        click_on I18n.t('doorkeeper.authorizations.buttons.authorize')
+        expect(page).to have_current_path(/\A#{client_app.redirect_uri}/, url: true)
+
+        # It grants the app access to the account
+        expect(Doorkeeper::AccessGrant.exists?(application: client_app, resource_owner_id: user.id)).to be true
+      end
+
+      it 'when rejecting the authorization request' do
+        params = { client_id: client_app.uid, response_type: 'code', redirect_uri: client_app.redirect_uri, scope: 'read' }
+        visit "/oauth/authorize?#{params.to_query}"
+
+        # It presents the user with a log-in page
+        expect(page).to have_content(I18n.t('auth.login'))
+
+        # Failing to log-in presents the form again
+        fill_in 'user_email', with: email
+        fill_in 'user_password', with: 'wrong password'
+        click_on I18n.t('auth.login')
+        expect(page).to have_content(I18n.t('auth.login'))
+
+        # Logging in redirects to a two-factor authentication page
+        fill_in 'user_email', with: email
+        fill_in 'user_password', with: password
+        click_on I18n.t('auth.login')
+        expect(page).to have_content(I18n.t('simple_form.hints.sessions.otp'))
+
+        # Filling in an incorrect two-factor authentication code presents the form again
+        fill_in 'user_otp_attempt', with: 'wrong'
+        click_on I18n.t('auth.login')
+        expect(page).to have_content(I18n.t('simple_form.hints.sessions.otp'))
+
+        # Filling in the correct TOTP code redirects to an app authorization page
+        fill_in 'user_otp_attempt', with: user.current_otp
+        click_on I18n.t('auth.login')
+        expect(page).to have_content(I18n.t('doorkeeper.authorizations.buttons.authorize'))
+
+        # Upon denying, it redirects to the apps' callback URL
+        click_on I18n.t('doorkeeper.authorizations.buttons.deny')
+        expect(page).to have_current_path(/\A#{client_app.redirect_uri}/, url: true)
+
+        # It does not grant the app access to the account
+        expect(Doorkeeper::AccessGrant.exists?(application: client_app, resource_owner_id: user.id)).to be false
+      end
+    end
+
+    # TODO: external auth
+  end
+end
diff --git a/spec/rails_helper.rb b/spec/rails_helper.rb
index c204fcdbd..de15cb785 100644
--- a/spec/rails_helper.rb
+++ b/spec/rails_helper.rb
@@ -44,6 +44,7 @@ RSpec.configure do |config|
 
   config.include Devise::Test::ControllerHelpers, type: :controller
   config.include Devise::Test::ControllerHelpers, type: :view
+  config.include Devise::Test::IntegrationHelpers, type: :feature
   config.include Paperclip::Shoulda::Matchers
   config.include ActiveSupport::Testing::TimeHelpers
   config.include Chewy::Rspec::Helpers